There is conventionally known an electronic device that includes an electric element stacked in two or more stages, and is sealed with a sealing part such as a sealing resin. When two or more electric elements are stacked in this manner, there has been used an aspect in which the electric element and a conductor layer are connected by a plurality of wires. However, when an upper electric element generates heat, heat dissipation has not been sufficient as compared with that of a lower electric element, since the heat is dissipated through the wire or the lower electric element.
In this regard, it has been proposed to provide an interposer between the electric elements in order to improve heat dissipation properties (e.g., see JP 2013-222905 A). However, since providing such an interposer requires one extra member, it has been expected to improve heat dissipation properties with a simple configuration without providing such a member.